ICD-10 code for essential hypertension and what to document.
I10 is the code for essential (primary) hypertension. When heart disease or chronic kidney disease is also present, the classification presumes a link and the code moves to I11, I12 or I13.
Updated · IntelliNotes product team
ICD-10 code for essential hypertension
I10, Essential (primary) hypertension, is the code for hypertension with no heart or kidney involvement classified elsewhere. Its inclusion terms cover high blood pressure and hypertension described as arterial, benign, essential, malignant, primary or systemic, so those words do not change the code. Heart disease, chronic kidney disease or a secondary cause does change it.
I10 and the codes that replace it
| Code | Official FY2026 descriptor | What the note must support |
|---|---|---|
| I10 | Essential (primary) hypertension | Hypertension without heart or kidney involvement classified to I11–I13, and not documented as secondary. |
| I11.9 | Hypertensive heart disease without heart failure | Hypertension with a heart condition classified to I51.4–I51.7, I51.89 or I51.9, without heart failure. |
| I11.0 | Hypertensive heart disease with heart failure | Hypertension with heart failure; add a code for the type of heart failure (I50.-). |
| I12.9 | Hypertensive chronic kidney disease with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease | Hypertension with CKD stage 1 to 4 or unspecified stage; add the stage code (N18.1–N18.4, N18.9). |
| I12.0 | Hypertensive chronic kidney disease with stage 5 chronic kidney disease or end stage renal disease | Hypertension with CKD stage 5 or end stage renal disease; add N18.5 or N18.6. |
| I13.10 | Hypertensive heart and chronic kidney disease without heart failure, with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease | Hypertension with both heart disease and CKD stage 1 to 4 or unspecified, without heart failure. |
| I13.0 | Hypertensive heart and chronic kidney disease with heart failure and stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease | Hypertension with heart failure and CKD stage 1 to 4 or unspecified; add I50.- and N18.- codes. |
| I13.11 | Hypertensive heart and chronic kidney disease without heart failure, with stage 5 chronic kidney disease, or end stage renal disease | Hypertension with heart disease and CKD stage 5 or end stage renal disease, without heart failure. |
| I13.2 | Hypertensive heart and chronic kidney disease with heart failure and with stage 5 chronic kidney disease, or end stage renal disease | Hypertension with heart failure and CKD stage 5 or end stage renal disease; add I50.- and N18.- codes. |
| I1A.0 | Resistant hypertension | Apparent treatment resistant, treatment resistant or true resistant hypertension documented; added after the hypertension code. |
| R03.0 | Elevated blood-pressure reading, without diagnosis of hypertension | An elevated reading in a patient without an established hypertension diagnosis. |
What the note must state
Heart and kidney involvement: the presumed causal link
The classification presumes a causal relationship between hypertension and heart involvement, and between hypertension and kidney involvement, because the Alphabetic Index links them with “with.” They are coded as related even when the note does not link them, unless the note clearly states they are unrelated (I.C.9.a, I.A.15). If the clinician considers the heart or kidney condition unrelated, the note must say so; then I10 is coded with the separate condition. For other conditions not linked by the classification, the note must state the link for them to be coded as related.
Heart disease and heart failure
Hypertension with heart failure (I50.-) or with a heart condition classified to I51.4, I51.89 or I51.9 is coded to category I11, with an additional code for the heart condition. Hypertension with I51.5 or I51.7 is also coded to I11, with no additional code (I.C.9.a.1). Document the type of heart failure so it can be coded from I50.-.
Chronic kidney disease and its stage
Hypertension with chronic kidney disease is coded to category I12, with an N18 code for the stage of the kidney disease (I.C.9.a.2). Document the stage. If diabetes is also present, category N18 has a “code first” note for both diabetic chronic kidney disease (E11.22) and hypertensive chronic kidney disease (I12.-, I13.-).
Heart disease and kidney disease together
When hypertension, heart disease and chronic kidney disease are all present, assign a combination code from I13, not codes from I11 and I12 (I.C.9.a.3). Add an I50 code if heart failure is present and an N18 code for the stage.
Secondary hypertension
Secondary hypertension needs two codes: one for the underlying cause and one from I15 (I.C.9.a.6). The note must name the underlying condition.
Controlled, uncontrolled, resistant and crisis
“Controlled” and “uncontrolled” do not have separate codes: both are assigned to the appropriate code from I10–I15 (I.C.9.a.8, I.C.9.a.9). When the clinician documents apparent treatment resistant, treatment resistant or true resistant hypertension, I1A.0 is added after the code for the type of hypertension (I.C.9.a.12). Documented hypertensive urgency, emergency or unspecified crisis is coded from I16, together with any identified hypertensive disease (I.C.9.a.10).
Tobacco use and exposure
The hypertensive diseases section (I10–I1A) instructs you to use an additional code to identify tobacco use, tobacco dependence, a history of tobacco dependence or exposure to environmental tobacco smoke. Record tobacco status in the note.
Codes that are often confused
- I10 vs I12.9: hypertension with chronic kidney disease stage 1 to 4 is I12.9 plus the N18 stage code, unless the note states the kidney disease is unrelated.
- I11.0 plus I12.9 vs I13.0: hypertension with heart failure and chronic kidney disease is one I13 combination code, not two codes.
- I10 vs R03.0: an elevated reading without an established diagnosis of hypertension is R03.0 (I.C.9.a.7).
- I10 vs I15.-: hypertension due to an underlying condition is secondary hypertension, coded from I15 with the cause.
Sample note drafted in IntelliNotes
This draft uses the SOAP sections that IntelliNotes generates from a selected diagnosis. I10 is supported because the note states essential hypertension, records tobacco status and documents that no heart disease or chronic kidney disease was identified.
SUBJECTIVE:
- Chief Complaint: Follow-up visit for hypertension.
- History of Present Illness (HPI): Patient in their 60s with essential hypertension, on a long-term antihypertensive medication. Home blood pressure readings reviewed and reported as stable. Reports taking the medication as prescribed. Denies headache, chest pain, shortness of breath and leg swelling.
- Review of Systems (ROS): Negative for vision changes, palpitations, chest pain, dyspnea and edema.
- Past Medical History: Essential hypertension. No history of heart failure or chronic kidney disease. Never smoker.
- Current Medications: Antihypertensive medication (long-term use).
- Allergies: Not documented.
OBJECTIVE:
- Vital Signs: BP 132/82 mmHg seated, repeat 128/80 mmHg; HR 68 bpm.
- Physical Examination: Regular heart rate and rhythm, no murmurs. Lungs clear to auscultation. No peripheral edema.
- Lab results: Basic metabolic panel within reference range. Urinalysis negative for protein.
ASSESSMENT:
- Primary diagnosis: Essential (primary) hypertension, documented by the clinician as controlled on current therapy. No heart disease or chronic kidney disease identified.
- ICD-10 codes:
I10 - Essential (primary) hypertension
PLAN:
- Treatment plan: Continues current antihypertensive medication; adherence reviewed.
- Medications prescribed: No changes documented.
- Follow-up: Return visit scheduled.
- Patient education provided: Home blood pressure measurement technique reviewed.
- Referrals: None documented.
Frequently asked questions
What is the ICD-10 code for essential hypertension?
I10, Essential (primary) hypertension. Its inclusion terms cover high blood pressure and hypertension described as arterial, benign, essential, malignant, primary or systemic. It does not apply when the hypertension is secondary (I15.-) or when heart or kidney involvement moves the code to I11, I12 or I13.
Do controlled or uncontrolled hypertension have their own codes?
No. The FY2026 guidelines (I.C.9.a.8 and I.C.9.a.9) assign controlled and uncontrolled hypertension to the appropriate code from categories I10–I15. Resistant hypertension is different: I1A.0 is added to the hypertension code when it is documented.
When does hypertension with kidney disease use I12 instead of I10?
When hypertension and chronic kidney disease are both present and heart disease is not. The classification presumes the link, so I12.- applies with an N18 code for the stage, unless the clinician documents that the kidney disease is not related to the hypertension. With heart disease as well, use I13.- instead.
What is the code for an elevated blood pressure reading without a hypertension diagnosis?
R03.0, Elevated blood-pressure reading, without diagnosis of hypertension. Guideline I.C.9.a.7 applies it unless the patient has an established diagnosis of hypertension.
Sources
Codes and descriptors were checked on November 10, 2026 against the FY2026 ICD-10-CM code set (effective October 1, 2025 through September 30, 2026), including the April 1, 2026 update.
- CDC NCHS: FY2026 ICD-10-CM code descriptions (ZIP)
- CDC NCHS: FY2026 ICD-10-CM Tabular List and Alphabetic Index (ZIP)
- CDC NCHS: ICD-10-CM Official Guidelines for Coding and Reporting FY 2026 (PDF)
- CMS: April 1, 2026 ICD-10-CM code descriptions in tabular order (ZIP)
- CMS: FY 2026 ICD-10-CM Coding Guidelines (PDF)
- CMS: ICD-10 code files and guidelines
Educational documentation guidance, not medical or coding advice. Confirm codes against the current code set and payer rules.
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